Note : For pre-compiled binaries for windows, both for win32 and win64, see the main web page.
There is currently only one way of building libsndfile for Win32 and Win64; cross compiling from Linux using the MinGW cross compiler.
libsndfile is written to be compiled by a compiler which supports large chunks of the 1999 ISO C Standard. Unfortunately, the microsoft compiler supports close to nothing of this standard and hence is not suitable for libsndfile.
It may be possible to compile libsndfile on windows using the MinGW compiler suite, but I haven't tested that and have no interest in supporting that.